Graft polymerization of sodium salt of 6-sulfohexyl methacrylate (SSHMA) or sodium salt of 8-sulfo-octyl methacrylate (SSOMA) onto segmented polyether urethane (SPEU) film was investigated.Graft reaction included two steps: f irst

hydroperoxide group was introduced onto the surface of SPEU through photo-oxidation in the presence of hydrogen peroxide

then it was reduced by ferrous ion to initiate sulfoalkyl methacrylate grafting on SPEU surface. The effect of the concentration of sulfoalkyl methacrylate

the concentration of ferrous ion and reaction temperature on the graft polymerization was discussed. The grafted films posses higher percentage of water absorption and anticoagulant activity than the ungrafted SPEU film. The salient micrographs on surface of grafted film were taken by scanning electronic microscope.